evolution unit test Flashcards
what are the 5 mechanisms
pinky - genetic drift
ring - non random mating
middle - mutations
pointer - gene flow
thumb - natural selection
what are mutations\
changes that occur in DNA
only source of new alleles
what is beneficial mutation
mutations are rare but the environment selects them which results from them growing overtime
what is a neutral mutation
occur in no regions of genetic material so it doesn’t harm or benefit the organism
what is a harmful mutation
occur frequently but environment selects against them so alleles that come from them are rare
what is natural selection
organisms with advantages heritable traits are selected for an survive and reproduce
what is selective pressure
selects for or against a certain traits that allows the organism to survive and reproduce a viable offspring
what are the 3 modes of natural selection
disruptive
directional
stabilizing
what is disruptive selection
selects for the extreme phenotypes
what is directional selection
selects for just one extreme aspect of trait
what is stabilizing selection
selects against the characteristics that differ form the most common ancestors
what are the 3 types of non random mating
inbreeding
preferred phenotypes
sexual selection
what is inbreeding
incest
what are preferred phenotypes
selects for a mate based on physical and behavioural traits
what are the 2 types of preferred phenotypes
disassortative
when a mate selects for someone who doesn’t look like them
assortative
when a mate selects for someone who is like them
what is sexual selection
when a female (most of the time) chooses a mate by their physical and behavioural traits (strongest, most colorful)
what is sexual dimorphism
the differences between females and males
difference between natural and sexual selection
natural focuses on reproductive and survival success but sexual focuses on passing of traits
difference between preferred phenotypes and sexual selection
allele frequency changes in sexual selection but not in preferred phenotypes
what is genetic drift
change in gene or allele frequency in small populations
what is the bottleneck effect (genetic drift)
large temporary reduction in the pop that results in lots of genetic drift
some alleles may be lost forever because only some individuals survive and reproduce
what is founders effect
when a small population leaves to make their own population distanced from old one
causes limited amount of alleles to be present
what is gene flow
movement of alleles from one pop to another by the moving of individuals
alters allele frequency
increases genetic diversity
what is macroevolution
progression of biodiversity over a long period of time
descent of many species from a common ancestor
involves speciation and extinction
what is microevolution
changes in allele frequencies within a population over successive generations
what is allele frequency
number of copies of an allele compared to the total number of alleles in a population
what are the 3 types of adaptations
structural
physiological
behavioural
what is structural adaptation
specific part or feature of organisms body
ex : fluffy feathers, mimicry, camouflage
what is physiological adaptation
permits an organism to preform a specific function
ex : hibernation
what is behavioural adaptation
ways an organism acts
ex : migration, hunting strategies
what is fitness ( reproductive success )
the relative contributor an organism makes to the next generation by producing offsprings that a VIABLE
what is variation
the difference between individuals
what are mutations
the starting point of genetic variation in populations
the changes in the DNA of an organism
- provide new alleles in a population
- the only source of new genetic variation within a species
what are adaptations
structure, behaviour, or physiological process that helps an organism survive and reproduce in a particular environment
what is biological evolution
an inherited change that happens within a population
changes in allele frequencies in populations
what is the connection between
mutations
variations
adaptations
An adaptation develops when a specific variation (random, heritable mutation in DNA) provides a select advantage
(genetic advantage that improves an organism’s chances of survival and reproduction)
This advantageous variation will gradually accumulate in a population
what is comparative anatomy
study of similarities and differences in anatomy between species
biochemical analysis
scientitist can determine how closely related two organisms are by comparing DNA and proteins
embryology
the study of early pre birth stages of an organism development
embryos of closely related organism often have similar stages in development
biogeography
the study of distribution of organisms and ecosystems in space and through geological time
what is the definition of a species
a group that has morphological differences from all other forms
what is speciation
the formation of new species
what are the 2 modes of speciation
allopatric :
Most new species form when a single species are separated by a geographical barrier
physical separation prevents the exchange of genetic information
sympatric :
Individuals within a population become genetically isolated from the larger population without geographic isolation
a population of a species within a single geographical region splits into separate gene pools and forms separate species.
how do populations become reproductively isolated in sympatric speciation
reproductive isolating mechanisms
what is reproductive isolating mechanisms
any behavioural structural or biochemical trait that prevents individuals of different species from reproducing successfully
what is prezygotic reproducing isolating mechanism
isolating mechanisms that prevent mating or fertilization
what is a postzygotic reproducing isolating mechanism
isolating mechanisms that prevent viable or fertile offspring
what are the 3 mating prevention’s (prezygotic)
ecological isolation
temporal isolation
behavioural isolation
what is ecological isolation
species that occupy separate habitats or separate niches of the same habitat do not meet to mate
what is temporal isolation
Temporal conditions refer to time of day, seasons or different years
Different species mate at different times
what is behavioural isolation
The courtship and mating cues for attracting a mate are very specific for each species
Distinctive mating rituals in one species will not be recognized by another
what are the 2 fertilizing prevention’s (prezygotic)
mechanical isolation
gametic isolation
what is mechanical isolation
Structural differences in reproductive organs prevent copulation (the key does not fit the lock)
what is gametic isolation
Prevents fertilization at the molecular level
Egg and sperm fail to fuse
what are the postzygotic reproducing isolating mechanisms
zygotic mortality
hybrid inviability
hybrid infertility
what is zygotic mortality
Fertilized zygotes die before birth
Chromosomes are not compatible
what is hybrid inviability
The embryo develops and dies before birth or is born alive, experiences reduced survival and does not survive to reproduce
what is hybrid infertility
Hybrids do develop normally and reach sexual maturity, but are sterile (do not produce viable gametes)
what are fossils
a fossil is a chronological collection of a life’s remains n sedimentary rock layers, tar pits
shows history of life by showing the kinds of species that were alive in the past
